Sightly distressed with high reactivity, i.e. their insomnia varies depending on their environment and life events

Slightly distressed with low reactivity

All the participants had their brain activities monitored via an electroencephalogram to determine any differences between patients.

They were also interviewed for how well they have responded to the commonly-prescribed sleeping pills benzodiazepines and cognitive behavioural therapy (CBT).

Benzodiazepines increase the effect of a chemical called GABA, which reduces brain activity and causes sedation.

Although often highly effective initially, the brain adjusts to these effects over time, with many people finding benzodiazepines stop working if taken continuously over several months, according to the charity Mind.

CBT also aims to relieve insomnia by changing people’s sleeping habits and their misconceptions about insomnia, which can make nodding off difficult.

Results revealed insomnia sufferers are made up of the following five sub-types: